One-way clutch with electromagnetic brake controlled backstop



June 15, 1965 .1. A. MARLAND ETAL 3,139,145 I ONE-WAY CLUTCH WITH ELECTROMAGNETIC BRAKE CONTROLLED BACKSTOP 2 Sheets-Sheet 1 Filed June 7, 1962 lllIIIl llll gENTORSJ 05% .3; 0/147 wWwfl Jun 1965 J. A. MARLAND ETAL 3,

ONE-WAY CLUTCH WITH ELECTROMAGNETIC BRAKE CONTROLLED BACKSTOP Filed June 7, 1962 2 Sheets-Sheet 2 se INVENZIYZZ @1545 $2,?

tween the partition 24 and the end Wall 14. The inner race 56 is spaced from the ball bearing assembly 46 by means of a spacing ring 58, and is secured on the sleeve 48.

The inner race 56 is provided with a plurality of spaced indentations 60 which define inclined planes 62. A cage 64 with a plurality of rollers 66 is disposed about the inner race 56 with a roller disposed in each indentation 60 thereof. A cylindrical outer race 68 is disposed about the cage and has a cylindrical inner surface confronting the cage 64.

The cylindrical outer race 68 is mounted on .a hub 70 disposed between the end of the sleeve 48 and the plate 32. The hub 70 is mounted on and affixed to the shaft 36 and rotates therewith.

An electromagnetic brake 72 is mounted on the plate 38 at the end 16 of the housing 10 and coupled to the sleeve 48. This electromagnetic brake 72 has a cup shaped hub 74 which is mounted on the sleeve 48 adjacent to the partition 24. The hub 74 has a plurality of spaced fingers 76 which extend therefrom along a cylindrical coaxial plane about the axis of the shaft 36 toward the end wall 16. A plurality of brake discs 78, which are provided with outwardly extending tabs 80, are mounted within the fingers 76 of the hub 74, the tabs 80 being disposed between adjacent fingers to prevent rotation of the discs 78 relative to the hub 74.

A brake drum 82 is disposed within the fingers 76 of the hub 74, and the drum 82 is provided with a plurality of spaced ribs 84. A brake disc 86 is disposed between each pair of adjacent brake discs 78, and the brake discs 86 have outwardly protruding tabs 88 which engage the ribs 84 on the drum 82. The drum 82 has a plate shaped portion mounted coaxially about the shaft 36 and designated 90, and this plate shaped portion is provided with a plurality of bores 92 disposed coaxially about the shaft 36. A locking bolt 94 extends through each of the bores 92 and is anchored in a plate 96 disposed adjacent to and affixed on the end plate 38.

The plate 96 also has mounted thereon a ferromagnetic ring 98 which is provided with a groove 100 in its surface remote from the end 16 of the housing. The groove 100 extends circularly about the shaft 36 and has a rectangular cross-section. A coil 102 is disposed within the groove 100. A ferromagnetic disc 104 is disposed between the ferromagnetic ring 98 and the drum 82, and the disc 104 has a central aperture 106 disposed about the shaft 36 and permitting translation of the disc relative thereto.

The ferromagnetic ring 98 is provided with a plurality of circular recesses 108 which are disposed therein from the surface confronting the ferromagnetic disc 104, and the recesses 108 have axes disposed parallel to the shaft 36 at intervals spaced coaxially about the shaft. Each of the recesses 108 contains a spiral spring 110 which is spring biased outwardly and abuts the ferromagnetic disc 104 to exert an outward pressure thereon. The springs 110 spring-load the disc 104 in a direction away from the end wall 16 of the housing 10. The ferromagnetic disc 104 is provided with a spacer 112 in the form of a ring which abuts the confronting brake disc 86 and exerts pressure on the assembled brake discs 86 and 78. In this manner, the electromagnetic brake 72 is in locked position in the absence of a current flowing through the coil 102.

When the coil 102 is energized, the ferromagnetic disc 104 is attracted away from the brake discs 78 and 86 to release the electromagnetic brake. It is to be noted that the locking pins 94 extend through channels 114 in the ferromagnetic ring 98, and also channels 116 in a spacer ring 118 disposed within the opening 106 of the ferrmagnetic disc 104 and rotatably about the shaft 36.

FIGURE 4 illustrates the electrical circuit for releasing the electromagnetic brake 72. The coil 102 of the electromagnetic brake '72 is shown connected in a series circuit with three direct current power sources 116, 118 and 120 in the form of batteries. A switch 122 is electrically connected between one end of the coil 102 and the battery 120. A switch 124 is electrically connected between the same end of the coil 102 and the junction between the batteries 118 and 120, and a third switch 126 is electrically connected between the same end of the coil 102 and the junction between the batteries 116 and 118.

If only the switch 126 is closed, only the battery 116 is connected in series with the coil 102, thus establishing current through the coil 102 of a magnitude which will attract the ferromagnetic disc 104 slightly and partially release the electromagnetic brake 72. If the load on the one-way backstop is great and in the reverse direction, the current flowing through the coil 102 as a result of the battery 116 alone will be sufficient to permit slow backward rotation of the shaft 36, that is, rotation in the opposite direction from the free wheeling direction of the one-way clutch. However, if the switch 124 is closed rather than the switch 126 or 122, the current from the batteries 116 and 118 will flow through the coil 102 and be of a magnitude sufficient to provide a greater release of the electromagnetic brake. When the switch 122 is closed, and the switches 124 and 126 are open, current from all H three batteries 116, 118 and 120 flows through the coil 102, effecting complete release of the electromagnetic brake '72. If none of the switches 122, 124, or 126 is closed, the current flowing through the coil 102 is of zero magnitude and the brake 72 is engaged to a maximum.

Since the electromagnetic brake 72 provides the only mechanical connection between the shaft 36 and the housing 10, release of the electromagnetic brake 72 is effective to release the backstop. It is to be noted, that the mechanical connection to the housing 10 is through the locking pins 94, brake cylinder 82, hub 74, sleeve 48, and the one-way clutch provided by the inner race 56, cage 64, outer race 68, and hub 70 to the shaft 36.

A manual release mechanism 128 is also provided for the backstop in the event the electrical circuit fails or is not utilized. The manual release mechanism employs a pair of wedges 130 and 132 mounted on the forromagnetic disc 104 adjacent to the periphery thereof and in a horizontal plane on opposite sides of the shaft 36. The Wedges 130 have an inclined planal surface 134 which is disposed at an acute angle to the surface of the ferromagnetic disc 104 and which terminates at its lower edge nearer to the disc 104 than its upper edge. The wedges 130 and 132 are securely attached and mounted on the ferromagnetic disc 104.

A yoke 136 has a horizontal cross member 138 which has mounted thereon a vertically disposed rod 140. The rod 140 passes through an opening 142 in the cover 22 of the housing 10 and is translatably disposed therein. The yoke 136 also has a pair of depending arms 144 and 146 which extend downwardly from the cross member 138 adjacent to the side walls 18 and 20 of the housing 10. The arms 144 and 146 are parallel to each other, and each of the arms is supported by a bracket 148 which has three legs disposed in a triangular relationship. One of the legs 150 is mounted on the top wall 22 of the housing 10, and second leg 152 depends normally from the first leg 150. A third leg 154 of each of the brackets 148 interconnects the opposite ends of the legs 150 and 152 for rigidity. The brackets 148 slidably abut the legs 144 and 146 of the yoke 136 to prevent the yoke 136 from being forced laterally away from the ferromagnetic disc, 104.

The yoke 136 has a wedge 156 mounted on the end of the leg 144 and a second wedge 158 mounted on the leg 146 thereof remote from the top wall 22 of the housing, and the wedges 156 and 158 confront and abut the wedges 130 and 132 mounted on the ferromagnetic disc 104, respectively. Each of the wedges 156 and 158 has a planal surface 160 disposed parallel to the surface 134 d of the wedges 13%) and 132. Further, the surface 160 abuts the surface 134, so that translation of the yoke 136 in an upward direction forces the ferromagnetic disc 104 in a direction away from the brake cylinder 82, thus releasing the electromagnetic brake '72 to permit rotation of the backstop in the reverse direction.

A lever arm 162 is pivotally mounted at its end 164 on the top wall 22 of the housing 10, and the rod 140 of the yoke 136 is pivotally mounted on the lever arm 162 between the fulcrum point 164 and the opposite end of the rod 162. In order to prevent accidental release of the backstop, the force required to lift the lever arm at its end remote from its pivot point 162 is intentionally made substantial, of the order of fifty to seventy-five pounds. In this manner, the application of an intentional force to the lever arm 162 may be utilized to release the backstop, but the likelihood of accidental release is minimized.

The housing It is provided with a liquid lubricant, the body of liquid lubricant being designated 166, which extends to the surface of the outer race 68 of the one-way clutch. The partition 24 of the housing isprovided with openings 168 to permit free flow of liquid lubricant into the two compartments of the housing 10. Lubrication of the one-way clutch and electromagnetic brake "I2 is accomplished in the manner described in the in ventors patent application Serial No. 129,841, now Pat. No. 3,175,667, filed August 7, 1961, entitled One-Way Clutch With Splash and Gravity Flow Lubrication System.

Those skilled in the art will readily devise many modifications and improvements upon the invention hereinbefore set forth. It is therefore intended that the scope of the present invention be not limited by the foregoing disclosure, but rather only by the impending claims.

The invention claimed is:

1. A releasable device for limiting the rotation of a I member to one rotational direction comprising, in combination, a housing, a shaft journaled within the housing and extending from the housing, said shaft being adapted to be coupled to the member, a one-way clutch having a generally cylindrical first race, a generally cylindrical second race coaxially disposed about the first race, and a plurality of drive elements disposed between the first race and second race, said drive elements wedging between the first and second races responsive to a torque applied in one direction between the races and slipping freely between the races for torques applied to the races in the reverse direction, means for coupling one of the races to the shaft for rotation therewith, brake means having a stationary member mounted on the housing, a rotatable member, and spring means mechanically coupling the rotatable and stationary members, said brake means including electromagnetic means having an electrical circuit for reducing the coupling between the rotatable and stationary members responsive to the flow of electrical current through the circuit thereof, said electrical circuit including means for controlling the magnitude of the electrical current flowing through said circuit to control the coupling between the stationary and rotatable members of the brake means, and means for coupling the other race of the one-way clutch to the rotatable member of the electromagnetic brake means.

2. A releasable device for limiting the rotation of a member to one rotational direction comprising the elements of claim 1 wherein the electrical circuit of the electromagnetic brake means includes means for limiting the flow of current in said circuit to a value between a first and a second magnitude, the first magnitude being sufficient to substantially disengage the brake means and the second magnitude being sufiicient to permit slipping of the brake means.

3. A releasable device for limiting the rotation of a member to one rotational direction comprising, in combination, a housing, a shaft journaled within the housing and extending from the housing, said shaft being adapted to be coupled to the member, a sleeve coaxially journaled about the shaft, a one-way clutch having a generally cylindrical first race mounted coaxially on the sleeve, a generally cylindrical second race coaxially disposed on the first race, and a plurality of drive elements disposed between the first race and second races, said drive elements wedging between the first and second race responsive to a torque applied in one direction between the races and slipping freely between the races for torques applied to the races in the reverse direction, a hub mounted on the second race at one end of the sleeve and secured on the shaft, and 'brake means having a stationary member mounted on the housing, a rotatable member mounted on the sleeve adjacent to the stationary member, and spring means mechanically coupling the rotatable and stationary members, said brake means including electromagnetic means having anelectrical circuit for reducing the coupling between the rotatable and stationary members re-' sponsive to the flow of electrical current in the electrical circuit thereof, said electrical circuit including means for controlling the magnitude of the electrical current flowing through said circuit for controlling the coupling between the stationary and rotatable members of the brake means.

4. A releasable device for limiting the rotation of a member to one rotational direction comprising the elements of claim 3 wherein the stationary member of the electromagnetic brake has a ferromagnetic element with a circular recess therein, an electrical coil disposed within the recess, a ferromagnetic disc confronting the recess in said element, said disc being mounted for translation relative to the axis of the shaft and restrained from rotation, a brake drum mounted on the housing on the side of the disc opposite the element, a first group of flat circular brake discs mounted on the brake drum coaxial to the shaft, a second group of flat circular brake discs mounted on the rotatable member coaxially about the shaft, and the brake discs of said second group of brake discs being disposed between the brake discs of the first group, and the spring means biasing the disc toward the movable member, whereby the two groups of brake discs are compressed together.

5. A releasable device for limiting the rotation of a member to one rotational direction comprising, in combination, a housing, a shaft journaled within the housing and extending from the housing, said shaft being adapted to be coupled to the member, a one-way clutch having a generally cylindrical first race, a generally cylindrical second race coaxially disposed on the first race, and a plurality of drive elements disposed between the first race and second race, said drive elements wedging between the first and second race responsive to a torque applied in one direction between the races and slipping freely between the races for torques applied to the races in the reverse direction, means for couplingone of the races to the shaft for rotation therewith, an electro-magnetic brake including a stationary member mounted on the housing, said stationary member having a ferromagnetic element with a circular recess therein, an electrical coil disposed within the recess, a ferromagnetic disc confronting the recess in said element, said disc being mounted for translation relative to the axis of the shaft and restrainedfrom rotation, a brake drum mounted on the housing on the side of the plate opposite the element, a first group of fiat circular brake discs mounted on the brake drum, a rotatable member coupled to the other race for rotation therewith, a second group of flat circular brake discs mounted on the rotatable member, the brake discs of said second group being disposed between the brake discs of the first group, yieldable means associated with the plate for compressing the brake discs of the first and second group, said magnetic brake locking the rotatable member on the stationary member for a first magnitude of elec trical current flowing through the coil thereof and releasing the rotatable member from the stationary member for a second magnitude of electrical current in saidf'coil.

6. A releasable device for limiting the rotation of a member to one rotational direction comprising the elements of claim 5 in combination with mechanical means for releasing the first group of brake discs from the second group of brake discs. '7 p 7. A releasable device for limiting the rotation of a member to one rotational directioncomprising the elements of claim 5 in combination with a wedge mounted on the side of the disc opposite the element having an inclined plane at an angle to the surfaceofthe disc, an arm translatably mounted on the housing having a wedge thereon with an inclined plane parallel to and confronting the Wedge on the disc, and a lever mechanism for translating the arm. 7 p p 3. A releasable device for limiting the rotation of a member to one rotational direction comprising, in combination, a housing, a shaft journaled within the housing and extending from the housing, said shaft being adapted to be coupled to the member, a one-Way clutch having a generally cylindrical first race mechanically coupled to the shaft, a generally cylindrical second race coaxially disposed about the first race, and a plurality of drive elements disposed between the first race and second race, said drive elements Wedging between the first and second race responsive to a torque applied in one direction between the races and slipping freely between th e races for torques applied to the races in the reverse direction, means for coupling one of the races to the shaft for rotation therewith, a rotatable member mechanically coupled to the first race, and means mounted on the housing for braking the rotatable member comprising a brake drum mounted on the housing having a first group of flat circular brake discs mounted thereon parallel to each other, a second group of flat circular brake discs mounted on the rotatable member, the brake discs of the second group being disposed between the brake discs of the first group, spring bias means for compressing the brake discs of the first and second group, and actuation responsive wedge means operatively associated with the spring bias means for releasing the spring bias on the brake discs.

9. A releasable device for limiting the rotation of a member comprising the elements of claim 8 wherein the actuation responsive wedge means includes a lever arm, means for pivotally mounting the lever arm at one end, and a mechanical linkage between the spring bias means and the lever arm.

References Cited by the Examiner UNITED STATES PATENTS 2,209,776 7/40 Kiekhaefer. 2,595,418 5/52 Seely 192-93 2,901,067 8/59 Nicholson l9217 DAVID J. WILLIAMOWSKY, Primary Examiner. THOMAS J. HICKEY, Examiner. 

1. A RELEASABLE DEVICE FOR LIMITING THE ROTATION OF A MEMBER TO ONE ROTATIONAL DIRECTION COMPRISING, IN COMBINATION, A HOUSING, A SHAFT JOURNALED WITHIN THE HOUSING AND EXTENDING FROM THE HOUSING, SAID SHAFT BEING ADAPTED TO BE COUPLED TO THE MEMBER, A ONE-WAY CLUTCH HAVING A GENERALLY CYLINDRICAL FIRST RACE, A GENERALLY CYLINDRICAL SECOND RACE COAXIALLY DISPOSED ABOUT THE FIRST RACE, AND A PLURALITY OF DRIVE ELEMENTS DISPOSED BETWEEN THE FIRST RACE AND SECOND RACE, SAID DRIVE ELEMENTS WEDGING BETWEEN THE FIRST AND SECOND RACES RESPONSIVE TO A TORQUE APPLIED IN ONE DIRECTION BETWEEN THE RACES AND SLIPPING FREELY BETWEEN THE RACES FOR TORQUES APPLIED TO THE RACES IN THE REVERSE DIRECTION, MEANS FOR COUPLING ONE OF THE RACES TO THE SHAFT FOR ROTATION THEREWITH, BRAKE MEANS HAVING A STATIONARY MEMBER MOUNTED ON THE HOUSING, A ROTATABLE MEMBER, AND SPRING MEANS MECHANICALLY COUPLING THE ROTATABLE AND STATIONARY MEMBERS, SAID BRAKE MEANS INCLUDING ELECTROMAGNETIC MEANS HAVING AN ELECTRICAL CIRCUIT FOR REDUCING THE COUPLING BETWEEN THE ROTATABLE AND STATIONARY MEMBERS RESPONSIVE TO THE FLOW OF ELECTRICAL CURRENT THROUGH THE CIRCUIT THEREOF, SAID ELECTRICAL CIRCUIT INCLUDING MEANS FOR CONTROLLING THE MAGNITUDE OF THE ELECTRICAL CURRENT FLOWING THROUGH SAID CIRCUIT TO CONTROL THE COUPLING BETWEEN THE STATIONARY AND ROTATABLE MEMBERS OF THE BRAKE MEANS, AND MEANS FOR COUPLING THE OTHER RACE OF THE ONE-WAY CLUTCH OF THE ROTATABLE MEMBER OF THE ELECTROMAGNETIC BRAKE MEANS. 